Field of the Invention
The present invention relates to polypeptides having cellulolytic enhancing activity, catalytic domains, and cellulose binding domains, and polynucleotides encoding the polypeptides, catalytic domains, and cellulose binding domains. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides, catalytic domains, and cellulose binding domains.
Description of the Related Art
Cellulose is a polymer of the simple sugar glucose covalently linked by beta-1,4-bonds. Many microorganisms produce enzymes that hydrolyze beta-linked glucans. These enzymes include endoglucanases, cellobiohydrolases, and beta-glucosidases. Endoglucanases digest the cellulose polymer at random locations, opening it to attack by cellobiohydrolases. Cellobiohydrolases sequentially release molecules of cellobiose from the ends of the cellulose polymer. Cellobiose is a water-soluble beta-1,4-linked dimer of glucose. Beta-glucosidases hydrolyze cellobiose to glucose. Once the cellulose is converted to glucose, the glucose can easily be fermented by yeast into ethanol.
The conversion of lignocellulosic feedstocks into ethanol has the advantages of the ready availability of large amounts of feedstock, the desirability of avoiding burning or land filling the materials, and the cleanliness of the ethanol fuel. Wood, agricultural residues, herbaceous crops, and municipal solid wastes have been considered as feedstocks for ethanol production. These materials primarily consist of cellulose, hemicellulose, and lignin.
WO 2005/074647, WO 2008/148131, and WO 2011/035027 disclose isolated GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Thielavia terrestris. WO 2005/074656 and WO 2010/065830 disclose isolated GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Thermoascus aurantiacus. WO 2007/089290 discloses an isolated GH61 polypeptide having cellulolytic enhancing activity and the polynucleotide thereof from Trichoderma reesei. WO 2009/085935, WO 2009/085859, WO 2009/085864, and WO 2009/085868 disclose isolated GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Myceliophthora thermophila. WO 2010/138754 discloses an isolated GH61 polypeptide having cellulolytic enhancing activity and the polynucleotide thereof from Aspergillus fumigatus. WO 2011/005867 discloses an isolated GH61 polypeptide having cellulolytic enhancing activity and the polynucleotide thereof from Penicillium pinophilum. WO 2011/039319 discloses an isolated GH61 polypeptide having cellulolytic enhancing activity and the polynucleotide thereof from Thermoascus sp. WO 2011/041397 discloses an isolated GH61 polypeptide having cellulolytic enhancing activity and the polynucleotide thereof from Penicillium sp. (emersonii). WO 2011/041504 discloses isolated GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Thermoascus crustaceus. WO 2012/030799 discloses GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Aspergillus aculeatus. WO 2008/151043 discloses methods of increasing the activity of a GH61 polypeptide having cellulolytic enhancing activity by adding a soluble activating divalent metal cation to a composition comprising the polypeptide.
There is a need in the art for new enzymes to increase efficiency and to provide cost-effective enzyme solutions for saccharification of cellulosic material.
The present invention provides GH61 polypeptides having cellulolytic enhancing activity and polynucleotides encoding the polypeptides.